Add support for pickup protocol messages

[nain-F49FF806]

Ref: https://github.com/hyperledger/aries-rfcs/blob/main/features/0685-pickup-v2/README.md

[gmulhearn]

looking nice. is it in scope to add some tests? typically each message type will have 2 unit tests in the same file: 1 testing serialization/deserialization with minimal content/decorators, and 1 testing with maximum content/decorators. and also some tests for checking that the message type strings are determined correctly. Check the other messages in the messages crate for examples

[codecov-commenter]

Codecov Report

Merging #1018 (f8c478c) into main (3f1045c) will decrease coverage by 0.87%.
The diff coverage is 2.94%.

❗ Current head f8c478c differs from pull request most recent head 032d00f. Consider uploading reports for the commit 032d00f to get more accurate results

@@            Coverage Diff             @@
##             main    #1018      +/-   ##
==========================================
- Coverage   36.67%   35.81%   -0.87%     
==========================================
  Files         369      381      +12     
  Lines       21811    21845      +34     
  Branches     4010     4040      +30     
==========================================
- Hits         8000     7823     -177     
- Misses      11653    11861     +208     
- Partials     2158     2161       +3     

Flag	Coverage Δ
unittests-aries-vcx	35.81% <2.94%> (-0.87%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
messages/src/msg_types/registry.rs	68.75% <100.00%> (ø)
messages/src/msg_types/protocols/mod.rs	41.33% <33.33%> (-0.34%)	⬇️
messages/src/lib.rs	22.22% <0.00%> (-0.97%)	⬇️
...sg_fields/protocols/pickup/live_delivery_change.rs	0.00% <0.00%> (ø)
...c/msg_fields/protocols/pickup/messages_received.rs	0.00% <0.00%> (ø)
.../src/msg_fields/protocols/pickup/status_request.rs	0.00% <0.00%> (ø)
messages/src/decorators/transport.rs	0.00% <0.00%> (ø)
...ssages/src/msg_fields/protocols/pickup/delivery.rs	0.00% <0.00%> (ø)
...rc/msg_fields/protocols/pickup/delivery_request.rs	0.00% <0.00%> (ø)
messages/src/msg_fields/protocols/pickup/status.rs	0.00% <0.00%> (ø)
... and 3 more

... and 44 files with indirect coverage changes